The present disclosure is directed to pipe couplings, particularly vent pipes.
Fuel-burning appliances require an exhaust system in order to vent combustion by-products, including noxious gases, fine ash, and water vapor, to the exterior of a building containing the appliance. Such appliances can include, for example, furnaces, water heaters, boilers, room heaters, wood stoves, and pellet stoves. Single-wall and double-wall vent pipes have been developed in numerous types and sizes to meet the need for effective exhaust piping.
Exhaust systems generally include one or more sections of vent pipe, fittings and adapters, made from a ductile material, such as sheet metal. These components are assembled during installation and fit to the given space. Since vent pipes are usually located between walls, in attics, and in crawl spaces, where there is little room to work, the manipulation of the vent pipes and related fittings is difficult, particularly when connecting sections of vent pipe. The connection between adjoining sections of vent pipe must be secure to avoid venting combustion by-products into the living space.
It is typical to form male and female couplings on opposite ends of each vent pipe section to facilitate field connection of the sections. Numerous designs for bayonet or twist-type couplings exist, as illustrated in U.S. Pat. No. 6,811,190, for example. One commercial product using a twist-type coupling is the Type B Gas Vent family of products manufactured by Simpson Dura-Vent Company, Inc.
However, it remains desirable to obtain improved couplings for joining vent pipe sections of various types in order to provide a connection that is secure and easy to assemble in the field.